Synthetic resins and process of making same



Patented Mar. 17, 1936 UNITED STATES 2,034,597 SYNTHETIC RESINS AND PROGESS OF MAKING SAME Theodor Sutter, Basel, Switzerland, assignor, by

mesne assignments, to

tion, Dover, Del.

Ciba Products (lorlwrav No Drawing. Application'June 30,1931, Serial No. 548,038. In Switzerland July 9, 1930 11 Claims. (01. 260-130) This invention relates to synthetic resins from primary aromatic amines and aldehydes. It comprises the process for the manufacture of these resins,'the new products themselves, as well as the application of same in the industry of synthetic resins.

In the copending specifications, Serial No. 398,267, filed October 8, '1929, No. 400,153, filed October 16, 1929, and No. 400,154, filed October 16,

1929, there are described various substances which when added to condensation products made in the presence of a mineral acid from primary aromatic amines and formaldehyde compounds profoundly vary the properties of these products, for instance their fluidity, durability, solidity at raised temperature and the like. As

such additional substances there are named in the said specifications hardening agents consisting of aldehydic compounds, such as aldehydes,

substances which yield aldehyde, aldehyde condensation products capable of being hardened; also fiuxing agents, such as fusible aldehyde condensation products and others.

According to the said specifications, the finished acid-free, dried and comminuted amineformaldehyde-resin is incorporated with the added substance by mixing them together or by spraying or some similar operation.

It has been found on further investigation that the most complete homogeneity possible of the mixture is of the greatest importance for the-production of the best possible properties in the final product. By intermixture in a dry condition complete homogeneity can only be attained witha considerable expenditure of time. Moreover, many of the addition substances available are viscous, syrup-y or smeary masses which can be distributed uniformly in a substratum only with difficulty. When it is sought to overcome this objection by using solvents, the mixture must be afterwards freed from the solvent, which necessitates a further operation and loss.

It has now been found that very valuable products are obtained by adding an aldehydic compound to the condensation product resulting from the reaction of the primary aromatic amine and the formaldehyde compound in presence of the mineral acid at a stage prior to-the drying of firmly retain components of such substances which are not inconsiderably soluble in water, so that even by thorough washing only inconsiderable losses of such substances occur. In consequence of this property it is possible that many 5 additional substances, such as aldehydes and any kind of aldehyde condensation products, which may act merely as fluxing agents, or may develop a hardening action on the resins, may be combined directly in aqueous solution with the amine- 10 formaldehyde-resins and thereby to obtain not only a particularly uniform distribution but also to avoid the isolation of the additional substance which is frequently tedious and costly, for even oily and syrupy substances are uniformly pre- 15 cipitated by adsorption on the voluminous formaldehyde resins, there being obtained precipitates that are easily filtered, washed, dried and. pulverlzed. 1

The process of the invention is particularly 20 valuable for fixing the resins homogeneously on and in substrata, such as paper pulp, wood-meal, asbestine, paper, textile fabrics or the like. The more freely flowing products obtainable by this invention permit a more complete penetration 25 of the substratum and the application of lower pressures.

The introduction of the additional substances hereinbefore named may occur at any stage of the manufacture of the amine-formaldehyde- 30 resin. Slowly reacting aldehydic compounds, such as furfural or benzaldehyde, as well as aldehyde condensation products may be dispersed even in an acid condensation solution, in which case, when the resin is separated they are simul- 3 taneously thrown down. Additional substances soluble in bases, such as phenol alcohols or phenol resins, may be dissolved in the base serving for eliminating the acid and in this manner precipitated together with the resin. (By the term 40 "phenol alcohols" the products resulting from the reaction of formaldehyde upon phenols in presence of cold aqueous alkali are understood. They are also known as methylol;phe'nols, methylol-cresols, etc.). It is also practicable to 45 stir or knead powerfully the neutral or basic suspension of the separated amine-formaldehyde-resin with the additional substance, which for this purpose may be dissolved in a solvent miscible with water, or the said suspension may be mixed with an alkaline solution of a. phenolaldehyde condensation product and the latter then precipitated on the amine-formaldehyderesin by careful acidification. In all cases the mixed product, freedfrom acid, if necessary Example 1 Into the acid solution of the condensation prod-.

not from 93 parts of aniline, 500 parts of hydrochloric acid of '7 per cent. strength and '15 parts of formalin of 38 per cent. strength, there are run, while stirring well, 30 parts of furfural, and a caustic soda solution are added and the reddish colored resin which is precipitated is washed with water. This product is easily fusible and hardens when heated under pressure to a lustrous black material very stable to heat.

Example 2 93 parts of phenol are dissolved in 200 parts oi caustic soda solution of 20 per cent. strength, 200 parts of formaldehyde of 38 per cent. strength are added in the cold and the whole is allowed to stand for some days. The solution then contains a mixture of phenol-polyalcohols.

As another operation 380 parts of aniline are dissolved in 500 parts of concentrated hydrochloric acid and the solution is diluted and stirred with 300 parts of formaldehyde of 38 per cent. strength for 1 hour at50 C. Then into the mixture thus obtained there is run, while stirring well, the above phenol-alcohol solution which is taken up without turbidity; the whole is poured into so much dilute caustic soda solution that the magma produced becomes only feebly acid. The whole is now made alkaline with sodium carbonate, filtered and the solid matter washed. The light colored powder thus obtained shows extraordinarily good fluxing and hardens at temperatures above 140 C. to pressed bodies of remarkable mechanical and chemical resistance.

Example 3 A solution of cresol-polyalcohols (dior trimethylol cresols) is obtained in manner analogous to that described in Example 2 by substituting 108 parts of crude cresol for the phenol. When the condensation is complete 4000 parts of caustic soda solution of 4 per cent. strength are added and into this solution, while stirring, there is run a condensation solution made as described in Example 2 from. 380 parts of aniline, 2000 parts of hydrochloric acid of '7 per cent. strength and 300 parts of formaldehyde solution of 38 per cent. strength. The: amine-formaldehyde-resin and the cresol-polyalcohols are precipitated together. The solution must at the end he alkaline with sodium carbonate. The resin is filtered, washed and dried, and ground with parts offurfural. By pressing the product, bodies of very good properties are obtained.

Example 4 93 parts of aniline are dissolved in the equivalent quantity of dilute hydrochloric acid, 95 parts of formalin of 38 per cent. strength are added been poured in, the magma produced has only a feeble acid reaction; the residual acid is neutralized with sodium carbonate and the mass is heated to 60 C. and filtered. By washing, drying and comminuting the precipitate there is obtained a powder which can be pressed very characteristically.

, Example 5 D An acid condensation solution made from 93 parts of aniline, 80 parts of concentrated hydrochloric acid, 1000 parts of water and parts of the formaldehyde solution of 38 per cent. strength is allowed to flow into a strongly alkaline solution of phenol alcohols made by condensation of phenol with 1 mol. of formaldehyde in dilute alkaline solution and containing 25 parts of phenol-alcohol- The united solutions are made feebly alkaline with sodium carbonate and the precipitate thus obtained is filtered, washed and dried. The product can be pressed at 150 C. to bodies which are completely homogeneous.

Example 6 V 104 parts of anhydroformaldehydeaniline are stirred in 200 parts of warm water and 300 parts of hydrochloric acid of 12 per cent. strength are added. This mixture is stirred at 60-90 C. until everything is dissolved and, while still stirring, 15 parts of furfural are added. Then the whole is run into a solution of phenol-polyalcohols made by allowing to stand for several days 15 parts of phenol with 2 /2 equivalents of formaldehyde in a dilute alkaline solution, this solutionof phenol-polyalcohols having been first mixed with sufiicient sodium carbonate to neutralize the acid in the amine-resin solution. A voluminous precipitate is produced which isfiltered, washed and dried; the powder flows very well under pressure to produce compressed bodies.

Example 7 108 parts of cresylic acid are dissolved in 200 parts of caustic soda solution of 20, per cent. strength, 280 parts of a formaldehyde solution of 38 per cent. strength are added in the cold and the whole is allowed to stand for some days. Then 40 parts of formaldehyde of the same strength are added and the mixture is run, while stirring well, into a solution of 186 parts of analine in 3000 parts of hydrochloric acid of 3.6 per cent. strength at a temperature of 40 C. After stirring well during one hour at 40 C., the mass is neutralized by addition of carbonate of sodium, filtered and the solid matter washed. By pressing the powder at a temperature above C., bodies of very good properties are obtained.

Example 8 93 parts of aniline are dissolved in 1000 parts of hydrochloric acid of 3.7 per cent. strength and added with 100 parts of a formaldehyde solution of 38 per cent. strength. After stirring during 20 minutes at 40 C. the condensation product is precipitated by 1000 parts of caustic soda solution of 4 per cent. strength. To the neutral pre-' cipitated mass an acid solution of the condensation product of 46 parts of aniline, 500 parts of hydrochloric acid of 7 per cent. strength and 3'7 parts of a formaldehyde solution of 38 per cent. strength is poured while stirring and by addition of caustic soda solution the condensation product is thrown down upon the suspension of the first precipitated condensation product. A very homogeneous mixture of the two precipitates is obtained, which will be filtered, washed, dried and comminuted. The white powder can be molded under adequate heat or pressure into bodies of very good qualities.

The term Primary aromatic amine, as employed in this application, is intended to cover not only true primary aromatic amines, such as aniline and its homologues, but also such derivatives thereof which under the conditions of the condensation described herein, also act like the true primary aromatic amines under the conditions of the present process to yield the same resins, for example, anhydroformaldehydeant line, formylaniline or the homologues of these compounds, and the like.

The expression Formaldehyde yielding compounds as employed herein, is intended to cover not only formaldehyde itself, but its polymers or any other substances splitting off formaldehyde or capable of forming methylene links under the conditions of the condensation, as it has been found that such substances or polymers may also be used in place of formaldehyde itself.

The term Synthetic resinous material, as used in this specification and claims, is intended to cover not only the pure resin, but all forms in which such resin may occur, namely, resin solutions, molding powder, molded article, impregnated cellulose material, in sheet form or loose, with or without the addition of fillers, plastifiers, coloring materials, and the like.

What I claim is:

1. The step in the process of manufacturing synthetic resins from amine-formaldehyde condensation products obtained by reacting a primary aromatic amine with a formaldehyde yielding compound in the presence of a mineral acid and subsequently precipitating the product by an agent of alkaline character, which comprises adding an aldehyde to the condensation product resulting from the reaction of the primary aromatic amine and the formaldehyde yielding compound in the presence of the mineral acid at a stage prior to the drying of the resinous material, whereby the said aldehyde is homogeneously adsorbed by said condensation product.

2. The step in the process of manufacturing synthetic resins from amine-formaldehyde condensation products obtained by reacting aniline with a formaldehyde yielding compound in the presence of a mineral acid and subsequently precipitating the product by an agent of alkaline character, which comprises adding an aldehyde to the condensation product resultingfrom the reaction of the aniline and the formaldehyde yielding compound in the presence of the mineral acid at a stage prior to the drying of the resinous material, whereby the said aldehyde is homogeneously adsorbed by said condensation product.

3. The step in the process of manufacturing synthetic resins from amine-formaldehyde condensation products obtained by reacting a primary aromatic amine with a formaldehyde yielding compound in the presence of a mineral acid and subsequently precipitating the product by an agent of alkaline character, which comprises adding furfural to the condensation product resulting from the reaction of the primary aromatic amine and the formaldehyde yielding compound in the presence of the mineral acid at a stage prior to the drying of the resinous material.

4. The step in the process of manufacturing synthetic resins from amine-formaldehyde condensation products obtained by reacting aniline with a formaldehyde yielding compound in the presence of a mineral acid and subsequently precipitating the product by an agent of alkaline character, which comprises adding furfural to the condensation product resulting from the reaction of the aniline and the formaldehyde yielding compound in the presence of the mineral acid at a stage prior to the drying of the resinous material.

5. The process of manufacturing synthetic resinous material which comprises reacting a primary aromatic amine and a formaldehyde yielding compound in the presence of a mineral acid to form a condensation product, adding an aldehyde to the acid solution of the condensation product, and, thereafter treating thesolution with an agent of alkaline character,- which causes the precipitation of the condensation product and the aldehyde, whereby the said aldehyde is homogeneously adsorbed by said condensation product.

6. The process of manufacturing synthetic resinous material which comprises reacting aniline and a formaldehyde yielding compound in the presence of a mineral acid to form a condensation product, adding an aldehyde to the acid solution of the condensation product, and thereafter treating the solution with an agent of alkaline character, which causes the precipitation of the condensation product and the reactive aldehydic compound, whereby the said aldehyde is homogeneously adsorbed by said condensation product.

7. The process of manufacturing synthetic resinous material which comprises reacting a primary aromatic amine and a formaldehyde yielding compound iri the presence of a mineral acid to form a condensation product, treating the solution with an agent of alkaline character and adding an aldehyde to the suspension of the precipitated condensation product, said aldehyde being capable of adsorption by said condensation product, whereby homogeneous admixture thereof is assured.

8. The process of manufacturing synthetic resinous material which comprises reacting aniline and a formaldehyde yielding compound in the presence of a mineral acid to form a condensation product, treating the solution with an agent of alkaline character and adding an aldehyde to the suspension of the precipitated condensation product, said aldehyde being capable of adsorption by said condensation product, whereby homogeneous admixture thereof is as sured.

9. A synthetic resinous material comprising a condensation product of a primary aromatic amine and at most an equimolecularproportion of a formaldehyde yielding compound obtained in the presence of a mineral acid combined with furfural.

10. A synthetic resinous material comprising a condensation product of aniline and at most an equimolecular proportion of formaldehyde obtained in the presence of a mineral acid combined with furfural.

11. The step in the process of manufacturing synthetic resins from amine-formaldehyde condensation products obtained by reacting a primary aromatic amine with a formaldehyde yielding compound in the presence of a mineral acid and subsequently precipitating the product by an agent of alkaline character, which comprises adding an aldehyde to the condensation product resulting, from the reaction of the primary aromatic amine and the formaldehyde yielding compound in the presence of mineral acid, and insubstantial absence of unreacted 

